Patients had either never been treated for chronic hepatitis or failed standard treatment more than 1 year prior to the study. HCV RNA levels were determined using Cobas Amplicor HCV Monitor v2.0 (Roche, Pleasanton, CA); cryoglobulins levels were measured in the National Institutes of Health clinical pathology department. Eligibility for treatment with 375 mg/m2 of rituximab (Genentech, San Francisco, CA) weekly for 4 weeks included HCV infection with MC, vasculitis in at least one organ, and failure or inability to tolerate Fostamatinib mouse interferon-α/ribavirin

treatment.7 Leukopacks were collected before treatment and 4 and 12 months after treatment, and 50 mL blood was drawn 2, 6, 8, and 10 months after cessation of treatment. Cryopreserved, thawed peripheral Compound Library purchase blood mononuclear cells (PBMCs) were treated with Live/Dead Fixable Violet dye (Invitrogen, Carlsbad, CA) and stained with antibodies to CD19, CD20, CD10, CD27, and CD21 (BD Biosciences, San

Jose, CA), and to CD14, CD3, and CD56 (Biolegend, San Diego, CA). B cell lymphoma-2 (Bcl-2) (US Biologicals, Swampscott, MA) and Ki-67 (Millipore, Billerica, MA) intracellular stains were performed using BD Cytofix/Cytoperm kits (BD Biosciences). Samples were analyzed on an LSRII flow cytometer using FACSDiva 6.1 (BD Biosciences) and FlowJo software (TreeStar Inc., Ashland, OR). CD19+ B cells of >95% purity were obtained by negative bead selection (Miltenyi Biotec, Auburn, CA). Immature and mature B cell subsets (>90% purity) were subsequently separated using an EasySep Human CD10 Positive Selection kit (Stem Cell Technologies, Vancouver, Canada), incubated at 106 cells/mL in Roswell Park Memorial Institute 1640 medium with 10% fetal bovine serum (US Bio-Technologies, Pottstown, PA), 10 mM 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid, 100 IU/mL penicillin, 100 μg/mL streptomycin, and 2 mM L-glutamine (Mediatech, Herndon, VA) for 24hr. The cells were stained as above, fixed,

permeabilized, and stained with antibodies to cleaved caspase-3 and caspase-8 (Cell Signaling Technologies, Danvers, MA) and D4-GD1 (Imgenex, San Diego, CA). Prism 5 (GraphPad Software Inc, La Jolla, CA) was used to perform a Kruskal-Wallis test followed by Dunn’s post-test for analysis of three or more groups, and a Mann-Whitney test for analysis of two groups. P < 0.05 was considered significant. Multicolor flow cytometry 上海皓元医药股份有限公司 was used to phenotype B cells of HCV-infected patients with and without MC in comparison with control groups of chronic hepatitis B e antigen–positive HBV-infected patients and uninfected blood donors. HBV-infected patients were studied to assess general changes in B cell percentages and phenotype during chronic hepatitis. After setting time, single cell, and lymphocyte gates, CD19+ B cells were selected, and dead cells, T cells, NK cells, and macrophages were excluded (Fig. 1A). CD19+ B cells were divided into mature and immature subsets based on CD10 expression (Fig. 1B).